Fig. 2

In vitro enzymatic activity of recombinant PbLSD on resveratrol and lutein (a) Left panel: Structure of the stilbene resveratrol (I) and the products, 3,5-dihydroxybenzaldehyd (II) and 4-hydroxybenaldehyde (III) produced by the enzymatic activity of PbLSD. Right panel: Structure of the carotenoid lutein (IV) and the products, 3-hydroxy-α-ionone (V), 3-hydroxy-β-ionone (VI) and 4,9-dimethyldodeca-2,4,5,8,10-pentaene-1,12-dial; C14 dialdehyde; (VII)) (b) Thin-layer chromatography analysis of assays with the recombinant PbLSD and AtCCD1 proteins when applied to either resveratrol (left panel) or lutein (right panel) substrates. Assignment of products arising from resveratrol was based on the expectation that the additional hydroxyl group on compound II yields a higher polarity compound, increasing its tendency to stay in the more hydrophobic solid phase, thus slowing its migrate compared to compound III. Migration of the expected C14 dialdehyde (compound VII) product arising from the reaction of AtCCD1 on lutein is consistent with previous observations [22]. The products produced by recombinant PbLSD from resveratrol were further characterized by reverse-phase HPLC. The expected products are labeled on the chromatogram again based on retention of the less polar compound III in the more hydrophobic stationary phase, with compound II eluting faster in the hydrophilic aqueous phase